The present disclosure relates to an antenna for wireless communication devices and systems and, more specifically, to printed dipole antennas for communication for wireless multi-band communication systems.
Wireless communication devices and systems are generally hand held or are part of portable laptop computers. Thus, the antenna must be of very small dimensions in order to fit the appropriate device. The system is used for general communication, as well as for wireless local area network (WLAN) systems. Dipole antennas have been used in these systems because they are small and can be tuned to the appropriate frequency. The shape of the printed dipole is generally a narrow, rectangular strip with a width less than 0.05 λ0 and a total length less than 0.5 λ0. The theoretical gain of the λ/2 dipole (with reference to the isotropic radiator) is generally 2.15 dBi and for a dipole antenna (two wire λ/4 length, middle excited, also with reference to the isotropic radiator) is equal to 1.76 dBi.
The present disclosure is a printed dipole antenna for a wireless communication device. It includes a first conductive element superimposed on a portion of and separated from a second conductive element by a first dielectric layer. A first conductive via connects the first and second conductive elements through the first dielectric layer. The second conductive element is generally U-shaped. The second conductive element includes a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape. Each strip on a leg is dimensioned for a different center frequency λ0 than another strip on the same leg.
The first conductive element may be L-shaped and one of the legs of the L-shape being superimposed on one of the legs of the U-shape. The first conductive via connects the other leg of the L-shape to the other leg of the U-shape. Alternatively, the first conductive element may be connected to the ends of the strips by individual vias.
The first and second conductive elements are each planar. The strips may have a width of less than 0.05 λ0 and a length of less than 0.5 λ0.
The antenna may be omni-directional or directional. If it is directional, it includes a ground plane conductor superimposed and separated from the second conductive element by a second dielectric layer. A third conductive element is superimposed and separated from the strips of the second conductive element by the first dielectric layer. A second conductive via connects the third conductive element to the ground conductor through the dielectric layers. The first and third conductive elements may be co-planar. The third conductive element includes a plurality of fingers superimposed on a portion of lateral edges of each of the strips.
These and other aspects of the present disclosure will become apparent from the following detailed description of the disclosure, when considered in conjunction with accompanying drawings.